The present invention relates to a positioning device for a rotary wrench and, more particularly, to a positioning device for a rotary wrench to position a head of the rotary wrench in a desired angular position relative to a handle of the rotary wrench.
A typical rotary wrench includes a handle and a head rotatably coupled to the handle. The handle includes first and second arms having a slit formed therebetween. The first arm has a first screw hole, and the second arm has a second screw hole. The first and second screw holes have different spiral directions and are opposite to each other. The head is disposed in a holding space between the first and second arms and includes two studs formed on opposite sides of the head. The studs couple with the first and second screw holes. When the head is rotated in a direction relative to the handle, the first and second arms move toward each other to tightly clamp the head. On the other hand, when the head is rotated in a reverse direction relative to the handle, the first and second arms move away from each other to loosen the head. An example of such a rotary wrench is disclosed in U.S. Pat. No. 7,246,544. However, the positioning effect of the rotary wrench by threading coupling between the studs and the screw holes is not reliable.
Thus, a need exists for a positioning device for a rotary wrench to reliably position the head relative to the handle.